Farrell was the subject of controversy after he hired his wife, Emma Doyle, as his temporary parliamentary assistant for four months in the Dáil.

This was just two weeks after she was rejected by Farrell's Malahide Fine Gael Party branch as his replacement on Fingal County Council in 2011.

[11][12][13] On 30 September 2020, he was appointed Fine Gael’s spokesperson on Climate Action by party leader Leo Varadkar.

Farrell took Hertz Rent A Car to court after one of its vehicles knocked against his Audi A6 while its driver was engaged in an encounter with a spider which crawled along her arm at a traffic stop.

In 2018, a photograph - showing Farrell at the time he was supposed to have been injured holding a poster of himself on an electricity pole while standing on a ladder in Skerries - was shown in Dublin District Court.

Judge Coghlan also noted in court that a separate claim by Farrell for material damage to his car had been relinquished since the accident.